<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta name="viewport"
          content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Index</title>
    <link rel="stylesheet" href="https://cdn.bootcss.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
    <style>
        #login-form{
            width: 22.5rem;
            padding: 1.5rem;
            position: fixed;
            top: 50%;
            left: 50%;
            -webkit-box-sizing: border-box;
            -moz-box-sizing: border-box;
            box-sizing: border-box;
            -webkit-border-radius: .1rem;
            -moz-border-radius: .1rem;
            border-radius: .1rem;
            /*-webkit-box-shadow: 0 0 .1rem 0 #ddd;
            -moz-box-shadow: 0 0 .1rem 0 #ddd;
            box-shadow: 0 0 .1rem 0 #ddd;*/
            -webkit-transform: translate(-50%,-65%);
            -moz-transform: translate(-50%,-65%);
            -ms-transform: translate(-50%,-65%);
            -o-transform: translate(-50%,-65%);
            transform: translate(-50%,-65%);
        }
    </style>
</head>
<body>
<form id="login-form">
    <h4>登录</h4>
    <div class="form-group">
        <label for="email1">Email address</label>
        <input type="email" class="form-control" id="email1" name="email1" placeholder="Enter email">
    </div>
    <div class="form-group">
        <label for="password1">Password</label>
        <input type="password" class="form-control" id="password1" placeholder="Password">
    </div>
    <button type="submit" class="btn btn-primary">Submit</button>
</form>
</body>
</html>